text:
What causes a "BATT DISCHARGE" CAS message on the Phenom 100E?
In the Phenom100 POH the descriptions for the "BATT DISCHARGE" CAS message is "During a normal system operation, at least one battery is discharging."
I'm a bit confused as to what exactly does normal operation mean.

Do I get the message as soon as I turn on both batteries ?
Does it show during the starting sequence if the GPU or other StarterGenerator is connected ?

And most important where can I find this information? I have not been able to find it in the POH or any other manual
I've also found this video on youtube but it seams to be from an older version and while it is showing the message during the first engine start it doesn't show it for the second when BATT1 should be discharging for sure because it's used to power the DC buses. Moreover this video contradicts what I know for sure from the EV and the simulator.
I've also checked the K-codes for this particular CAS message and it has none

If it's like any other battery system, it should mean that the battery charger isn't working and the battery is discharging. It may soon be dead.

I don't work the Phenom but I have worked numerous aircraft that are capable of providing a BATT DISCHARGE message. In every case that I've seen, it comes because the battery is in use, but not being re-charged. For example, if a GPU is connected, and the batteries are on, the battery may be in use, but it is not DISCHARGING because it's being continuously charged by the GPU.

@Frank I've updated my question with an video from youtube the problem is that during the start of the second engine the CAS message is not showing

@RonBeyer unfortunately I don't think it's true, as you can see in the video in my updated answer the pilots get the message and I highly doubt that any sane pilot would takeoff with a dead/dying battery.

They might if they have another functioning battery and charger. I believe the Phenom has at least two batteries and chargers

Not familiar with the Phenom, but there are cases where a warning message will be suppressed by the EICAS system when the trigger condition is normal. For example, if starting a motor requires current that only the battery can provide, then during start you will always be in a "battery discharge" condition, but you won't get the caution message because what's happening is normal, rather than a failure of the charger. Don't know if that's what happens with the Phenom, but it would seem to be a possibility.

I worked on the software for the GCUs on the Phenom 100/300 (around 2008) but can't for the life of me remember when that unit might send a signal to the CAS that would generate that message. Unless the design has changed since then, there isn't a separate battery charger. The starter/generators are 28 VDC and the GCU uses contactors to control the connection to the batteries.

@toby It looks to me like this would be normal system ops. It's kind of like starting your car from the battery. The initial engine start pulls directly from the battery (and discharges it - not entirely but partly). Once it's running, the alternator is providing a constant 13-14 volts to the vehicle (and topping off the battery). This scenario applies to the engine start sequence as well. The first start pulls from the battery. Now you have an engine generator providing a source of power, presumably to a TR, which can support the next engine start on the DC/Battery Bus.

I am not into the Phenom 100E nor the avionics.
However, me and many others think that there is not much space for interpretation on this message.
In the G1000 handbook of the Phenom 100, on page 129 in the section "CAS Messages > Caution Messages", it says:

BATT DISCHARGE Battery discharging under normal operation

Source

Source (Page 122)
This is the electrical status page as shown on the G1000 of the Phenom 100E. I marked the batteries yellow and all parts actively generating electricity and affecting load of the batteries in red.
When will BATT DISCHARGE pop up?
BATT DISCHARGE will pop up, if the load on the batteries is higher than the charge. This applies in following situations:

Master is on and systems are consuming electricity from the batteries but no engine and generator is on and no GPU is connected to the aircraft.
If the message pops up during flight, in which GEN 1 and GEN 2 usually charge the batteries, there is a problem with the generators. Additionally there can be displayed an ELEC EMERGENCY warning on the CAS.

What we see in the video

Start of engine Nr. 2 When he starts the first engine, we can see three CAS-Messages: BATT DISCHARGE, SHED BUS OFF (definition of SHED BUS below) and GPU CONNECTED. The engines on a Phenom are cranked by electricity, not by pressure air, so the BATT DISCHARGE makes sense first. However, the GPU is connected. Now, many things could happen here. Maybe an engine start is using lots of power, even more than the GPU can deliver.

After start of Nr. 2 After the start (~ 1:32), we can see on the status page, that the GPU was disconnected. The Generator of ENG 2 is already running. On the CAS there is still the BATT DISCHARGE and GPU CONNECTED to see. They disappear at the same time. This is probably because of some delay in the CAS-System. That means the battery is discharging, even though the GPU is connected (~ 0:55). It could be because of a weak GPU.

Start of engine Nr. 1 (~ 1:58) When the second engine gets cranked up, we can see, that the GPU was removed shortly after start of engine Nr. 2. However, there is no BATT DISCHARGE caution message anymore. Now engine Nr. 2 charges the battery. Maybe the generator is stronger than the GPU before. While starting Nr. 1, the SHED BUS is off again.

Unfortunately the video doesn't show, when engine Nr. 1 has started and is stabilized. It would be interesting.
Personal conclusion
As already said, I am not a pilot nor an engineer and only have the knowledge I have self-taught. On this knowledge-basis, I would say following looks most logic for me:
The GPU delivers only a small amount of electricity to the plane. It can't balance the load of the battery. I don't know if this is possible, but looks logic for me. After engine start, the generators of engine Nr. 2 provide the aircraft with lots of power, enough to charge the battery and to start the other engine.
The theory of a GPU, providing only a small amount of electricity would be supported by how the SHED BUS works, below. The EDL disconnects the SHED BUS because the batteries are loosing power. You can see this at ~1:08 in the video in the ELEC section of the MFD. It shows: BATT 1 - 23.5V and BATT 2 - 25.8V. This is well below the normal voltage of 28V. A bit later at 1:28 we see that both batteries have dropped to ~24V and are still discharging. At ~1:30 we see the generators providing electricity and the batteries are charging again fastly. Thats also when the SHED BUS is coming on again. At 1:58 the SHED BUS is off again and the batteries are down at 22V and 25V.
So, when I look at the facts, it looks like a weak GPU for me. However, there is still one question: Why is there no BATT DISCHARGE when starting Nr. 1?
My theory is: It looks like there is some sort of delay in the CAS-System. As we have seen in the video, the GPU is already indicated to be disonnected on the MFD, but the CAS still says it is connected. Maybe the message BATT DISCHARGING hasn't appeared because of the delay. We lack the last seconds of the video, so we don't know if the message maybe appears or the generators provide electricity early enough, before appearing.
(I think this question needs more attention. It's a nice puzzle question that deserves much more upvotes.)

UPDATES

I have now found GPU values I can't confirm to be true:

GPU Limits
27V to charge
26-29V for operation
800-1000 Amps

Source

The SHED BUS

The shed bus powers non-essential aircraft systems. In the case of the phenom 100 this is things like the air conditioning, passenger power sockets and entertainment systems, the toilet and some lighting.
The shed bus is the first thing to lose power (be shed) should the aircraft not be generating enough electricity through, for example, a generator dropping offline.

From my question about the shed bus by sp1.

Thanks for the answer my problem is that actually if you look at the video in my answer at 1:08 we have the BAT DISCHARGE CAS message during the first engine start, but at 1:58 during the second engine start we don't and BATT1 is used to power the DC buses through EBC1 and QSC during the start sequence do you have any idea why there's no CAS message during the start of the SG2.

@toby I updated the answer. I will also continue researching and edit further if I find something new.


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How does the autopilot act when it receives an obviously bad temperature value?
Assuming the plane is on autopilot: for example, if a plane is flying high (over 20000 feet) and its autopilot receives a positive value of external temperature, which is clearly abnormal or impossible.
What will the autopilot do with such a obviously wrong information?

Hello mouniir oouli, welcome to Aviation.SE. Your question is not very clear. Could you explain what you mean by too high (about 20 tousand feets)?  What do you mean by enter in a new procedure or ask itself that it is not normal ?

Hello Mouniir. Are you asking what happens when the outer air temperature changes and about autopilot behavior?

Autopilot does not receive temperature at all. Only autothrust does, in Mach mode, indirectly, since Mach number depends on temperature.

You may want to open your question to all flight automatisms, rather than autopilot. Or you may want to know what would happen if the autopilot received wrong data from the units processing temperature sensor data (e.g. ADIRS).

airconditionning need the correct temperature  to work properly ..the sensors are located outside and should give the right value to the HVAC system ...and also to the antigel system actuator ..

The autopilot does not receive information about the outside temperature, it has no (direct) relation to what the autopilot controls.
The autopilot receives aircraft state inputs like airspeed, Mach number, vertical speed, attitude, accelerations etc.

I can not tell you what happens if there is a positive value for the temperature above 20000ft, but here is some general information:
For this issue I will be talking about Airbus planes, as they are known to be very "smart" planes. There are hundreds of algorithms that try to prevent wrong data input from being an issue. But those do not always work.
Take Qantas Flight 72 for example: According to Wikipedia the airplane all of the sudden pitched down violently, as if it was trying to prevent a stall from happening. This was because the average of the two angle of attack sensors was way out the box. Though there was a (very smart) algorithm rechecking the values, it could not deal with multiple wrong values with a certain amount of time - and made the airplane pitch down.
This being an example where the plane actually acted by itself due to a faulty value, here is the general case: If the airplane notices odd values, which it will usually recognize (e.g. a positive temperature), it blanks out the display so that a pilot can not be mislead.
When flying smaller airplanes, you often practice "partial panel flying", where your flight instructor covers up some instruments and you have to fly the aircraft with alternative instruments. As you can see this is well practiced and
shouldn't be a problem. Unfortunately though, this makes flying a lot harder which can cause crashes to happen (AF447,QZ8501, and more).
Furthermore, whenever the autopilot finds itself in a situation that it can't handle, for example when the pitot static system fails, it will disconnect and refuse to connect, giving the pilot full control (or rather as full control as possible on an Airbus) of the aircraft. This disengagement ensures the plane not to do something stupid due to wrong inputs.
Conclusion: For redundancy most systems exist two or three times working parallel to provide backup, same goes for sensors. If all data inputs report something obviously wrong, the pilot will not see this wrong information so he can concentrate on what he has.
The answers to this question can also give you a little more information about computer redundancy on aircraft

I don't see how this answers the question.  I would also welcome input from someone qualified as to whether OAT is used at all by the autopilot.  I don't think it is.

Well, as I said I cannot be specific, but I've listed a couple of scenarios what the autopilot will do with wrong inputs. The autopilot itself doesn't use the Oct but it is used for altitude and speed calculations by the system, so if they are wrong the autopilot might still get wring data.

Oh and @Simon calling someone unqualified though he gave an answer based on examples and documentation is quite rude, and I'd really appreciate removing that part of the comment.

I didn't mean to imply that you are not qualified and apologise if you perceive it as rude, which is never my intention.  I mean big iron certified aircrew.  Nor was I criticising you or your post.  Simply stating that I don't believe that it answers the question is not criticism, just a statement of opinion on a Q&A.  Cheers

Okay, cheers buddy

The question would be much more informative if it was expanded to include other 'failures', in which case your answer would be very good. But please please please remember that there is no 'U' in Qantas!!!

Haha oouhh that's being removed immediately!

thanky you Maverick . my question is related to Airbus because this Airplane is trusting the automatic navigation .  I am Against the Automatic Navigation of Machine because it killed the human intelligence . If we want automatic Navigation then we should do it without Pilot on Board . this a pragmatic Vision  but it can open a good way for a better conception of automatic Pilottin  systems on Board .

Depending on the 'architecture' or system design of the avionics, the autopilot may or, at today's levels of technology, may not directly receive temperature information.
The Temperature is taken from multiple systems of TAT (Total Air Temperature) probes and is fed to an ADC (Air Data Computer) or equivalent, which then analyses the inputs received for bad data and it will typically have redundancies that will allow it to discard the bad and provide only good data to it's 'clients', one client being the autoflight system.
Depending on the architecture and system features, the autoflight system or subsystem may even receive both, i.e. from the ADC and direct inputs from a local probe.
With the advent of FBW, Fly-by-wire, all data comes in for scrutiny by some computer or the other, and probably more than once.
Whether bad data can get past all the redundancies and cause an autopilot to misbehave, we can only answer that the chances are remote, but it can happen. Regarding a temperature input that is +ve above 20,000ft - this may not always be way out of line as, depending on the speed, the TAT could conceivably be around the 0degC mark at those levels at around Mach 0.7

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text:
What does 'outlook ... VFR' mean?
In most weather reports I see "Outlook VFR" and I am not sure what that means and as a pilot what should I expect? What is an "outlook" and what does it mean when it is "VFR"?
In other words, what does 'OTLK... VFR' mean in weather reports?

Outlook VFR is usually found in the so called "Area Forecast". It is the last part of the portion which describes clouds and weather, which could affect VFR operations.
The area forecast for every region is valid for 12 hours, followed by a 6 hour categorical outlook.
There are three types of outlooks, VFR, IFR and MVFR (marginal VFR). As mentioned in Jeppesen's Guided Flight Discovery Instrument/Commercial Manual:

A ceiling less than 1,000 feet and/or visibility less then 3 miles is
  considered IFR. Marginal VFR areas are those with ceilings from 1,000
  to 3,000 feet and/or visibility between 3 and 5 miles.

Everything "better" (as in higher ceiling and/or visibility) is considered VFR.
Here is an extract from an Area Forecast:
CLDS/WX VALID UNTIL 062100...OTLK VALID 062100-070300
[...]
NRN PEN...BKN010-020 TOP 100. OCNL VIS 3SM BR. BECMG 1214 BKN025
TOP 120. ISOL -SHRA. 18Z BKN040 TOP FL220. WDLY SCT -SHRA/TSRA.
CB TOP FL420. OTLK...VFR TIL 02Z SHRA TSRA.

The first part is an extract from the Heading Section. here you find the time for which the Clouds and Weather part as well as the Outlook part is valid.
The second part consist of the mentioned Clouds and Weather as well as the Outlook. I'm not going to decipher the whole thing now, but here is a short explanation:
You can see the more detailed forecast, valid from the time of loading the Area Forecast to 062100, which means the 6th of the month, 21:00 Zulu time. After that, from 062100-070300 so from the 6th at 21:00 Zulu until the 7th at 03:00 Zulu, the outlook is what counts. In this case it is VFR until the 7th of the month at 02:00 Zulu, where showers and thunderstorms (in connection with rain) are expected.
Conclusion: The outlook gives a general idea what the weather will be like up to 6 hours after the forecast part of the Are Forecast. This can help in flight planning.
For more information about VFR refer to DannyBeckett's detailed answer.

VFR stands for Visual Flight Rules, in which you can expect VMC - or Visual Meteorological Conditions. In other words, good weather conditions.

Conditions in which pilots have sufficient visibility to fly the aircraft maintaining visual separation from terrain and other aircraft.
It is the opposite of instrument meteorological conditions (IMC). The boundary criteria between IMC and VMC are known as the VMC minima and are defined by: visibility, cloud ceilings (for takeoffs and landings), and cloud clearances.

The FAA has regulations (14 CFR 91.155) on VFR Weather Minimums, and the following is taken from the VFR Weather Minimums PDF the FAA publishes:

VFR flight is based on the principle of “see and avoid.” The presumption
  made in establishing the basic VFR weather minimums is that aircraft
  flying at lower altitudes (i.e., below 10,000 MSL) and/or in airspace with
  radar approach control and/or an operating control tower (i.e., Class B, C,
  and D airspace) will be moving more slowly, or that they will be under
  positive control. Consequently, these aircraft do not need as much flight
  visibility or as much distance from clouds to see and avoid other traffic.
Aircraft operating at higher altitudes (i.e., Class E airspace above 10,000
  MSL) are likely to be not only faster, but also operating on instrument
  flight plans. The rationale for greater visibility and more distance from
  clouds when flying above 10,000 MSL is to give VFR pilots more time to
  see and avoid faster aircraft that are popping in and out of clouds.

when you see OTLK VFR does it mean bad weather or good weather?

@PMoubed VFR = "good" / IFR = "bad"

@PMoubed: Bad and good are entirely subjective.  As for instance, right about now I imagine most folks in California and the environs (of whom I'm one) would think about two weeks of solid IMC and pouring rain would be pretty darned good :-)

You should probably also explain the term outlook in your answer.

@Maverick283 yes, can somebody please explain the word "outlook"?

Just done so ;)

Even for flying purposes there are circumstances where IMC is preferable to VMC. It sure beats wearing that confounded hood.

this does not really answer the question.

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text:
Where can I find the latest METAR and TAF for RPVK / Kalibo International Airport?
What website holds the latest METAR and TAF for RPVK / Philippine weather?
In aviation weather the information does not exist at all times.
Could you suggest an other website that provides the required information.
Thanks for the help!

You can use the OGIMET database, but they only have one TAF for RPVK in the last 24 hours

Interestingly, the Philippine weather service only provides TAFs on their site. I don't know what to make of that.

You can find the latest METAR for RPVK here: https://tgftp.nws.noaa.gov/data/observations/metar/stations/RPVK.TXT and TAF here: https://tgftp.nws.noaa.gov/data/forecasts/taf/stations/RPVK.TXT
Remember to look at the publication date/time, since it may not be very recent.

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A320/321 FMA indications with Both Flight Director Channel Failed
I hope that someone can answer my question. My friend had “FD 1+2 Failure” in simulator during the low visibility approach. Flight Directors on PFD disappeared, but no FMA change and no approach capability downgrade. When a go-around was executed, lateral and vertical guidances of FMA went blank (SPD/ / ).
On the next approach, he captured G/S and LOC with both FDs failed, but no ROLLOUT indication after touch down.
Anybody can explain the logic behind this?
Thank you.

Can you clarify what the actual behavior is versus the expected behavior? You're asking people to explain the logic behind "this" but I'm not sure what "this" is.

FD1+2 Failed on approach.; (A) Go-around was executed, then FMA went blank (SPD/   /   ) with AP engaged. (B) The second Cat3 approach was successful with FD1+2 failed, but no ROLLOUT after touchdown. I would like to know why the FMA indicated like A and B with FD1+2 Failed.

FD and Autopilot share common FMA modes, so failure of FD 1+2 has no effect on FMA modes as long as AP(s) are engaged. The key information missing here is if G/A was flown manually (sounds so, as FMA went blank; ie both AP/FD disconnected) and if auto-rollout was attempted, which if I recall correctly should not be done without FDs. Again, after APs are off with FDs failed the FMA will go blank, including no ROLLOUT mode.

It was the AUTOMATIC G/A. And, on the second attempt, the AP remained engaged until he saw no ROLLOUT and disengaged AP.

On the A320, the FAC takes commands from the FMGC to compute the FD bars. The FD bars and  certain FMA annunciations and speeds are provided to the DMC for display on the PFD.
Your FD loss scenario is a partial FAC failure which is why AP continued to work, since the FG function of the FMGC was operational, but the FMA annunciations are faulty. Yaw control is also a function of the FAC which affects ROLLOUT.
See Airbus Safety First Magazine 23 for a similar scenario: the aircraft was operating with an ADR channel disabled under MEL, encountered windshear causing discrepant AOA measurements, the FACs only had two measurements so they tripped off causing the crew to lose FD, characteristic speeds, and FMA.

FDs stay shown with FMA indication when FAC1+2 Fault happens. So, it doesn’t make sense to me that the PARTIAL FAC failure caused him a loss of FDs and FMA when a G/A was executed.. I was not in the sim and have no clue how his IP set up this malfunction. But, I believe that IP just set him up for merely both FD channels fault and gave him those consequences (If it were caused by FAC fault, he should have seen FAC ECAM message).

@mach Because "FAC 1+2 fault" is another partial FAC fault representing loss of flight control functions. Computers in the A320 have segregated functions, often via hardware on different cards. This is also why there's a difference between the FAC reset PB and the FAC circuit breaker. The pilots didn't realize this, which caused the AirAsia crash.


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What are the opimum values of Cl during descent?
Statistical Analysis of A320 aircraft shows the Cl values to be as under: cl_value. L is assumed to be 0.5*MaximumLandingWeight of A320 as the Aircraft is about to land.
The Units used are: Flight Level(feet), rho(lb/feet^3, V(feet/s), for the sixth column, 1/2(rho.V^2.S.)

The cruise Cl values are as under:
When compared to cruise the CL during descent is very small. Is this an acceptable result?

If I'm understanding your question correctly, you should be assuming very close to 1.0 * MaximumLandingWeight. An airplane needs to lift its full weight in a stabilized descent.

possible duplicate of How to calculate the Lift Coefficient for the A320?

I assume you want to work in SI unit. If so, your third column should be in kg/m^3, currently the values are wrong. The fourth column I expect to be in knots, the fifth should be in m/s and is wrong. Consequently the sixth column isn't correct either and that explains why the C_L doesn't match your expectations.

Yes, CL is smaller during descent, and No, the values in your tables are not correct. You have a formula/unit conversion problem somewhere. Also 0.5 MLW is a bit too much a correction for descent. You are basically assuming 60deg downslope with is a lot even for a dive bomber. 3deg is more likely, and 0.998 is a better slope correction factor.

The ratio of $c_L$ over $c_D$ should be somewhere between 12 and 18. Your $c_L$ values are too small by more than an order of magnitude.

@FredLarson and Radu094 has said it well. It can drop like a rock, if it's landing? if there's a substantial downwards gravitational force (if L is not equal to W), the aircraft will accelerate downwards (assuming small angles for a decent landing). The question needs to be corrected of these errors, to avoid unnecessary explanations further.

@GürkanÇetin we could also add that L is most probably slightly bigger than W, since in a nose-down attitude (usually the case in a descent) the thrust has a component that helps the weight (a mirror situation of this case)

I am going to work in SI units for all engineering work, anything else would cause instant insanity on my side. I'll leave the altitude in feet (isn't used) and convert speed from knots to m/s so you can follow the flow easily. Since $C_L$ is unitless it should not matter what units you use in the calculation as long as you are consistent.

Altitude: 34000 [ft] (not used)
$V$ (true air speed): 442 [knots] = 227 [m/s]
S = 112.6 [m2]
$\rho_0$ = 1.225 [kg/m3]
$\frac{\rho}{\rho_0}$=0.322 [-] (from your table)
$\rho$ = $1.225 \cdot 0.322 = 0.394$ [kg/m3]
$\frac{1}{2}\rho V^2 S$ = $\frac{1}{2} 0.394\cdot 227^2 \cdot112.6 = 125\cdot10^4 $[N]
$m$ = MLM = 64500 [kg]
W = $m\cdot g$ = $64500\cdot 9.81$ = $63\cdot10^4$ [N]
$C_L$ = $\frac{W}{\frac{1}{2}\rho V^2 S}$=$\frac{63\cdot 10^4}{125\cdot 10^4}$ = 0.5

I did take full maximum landing mass for this calculation. If you want to apply corrections then note that the $C_L$ value scales linearly with the mass.
One further note:
I assume your data is derived from ADS-B. ADS-B transmits groundspeed, whilst you should work with true airspeed in these formula's. The difference between them is the tailwind (or headwind) component.

The difference between them is the tailwind (or headwind) component. It's a vector sum, so also the sidewind has an influence.

@Federico correct, but generally the effect is negligible for this kind of analysis. I didn't want to overcomplicate the matter.

For the analysis I might agree, for the TAS vs GS difference, a little less.

It should be noted that speed is "true airspeed". and a small correction: there's a "not" missing in the "it should matter" part..

@GürkanÇetin thank you, I've corrected it


text:
Which timezone do airspaces that cross a time zone boundary belong to on a VFR sectional?
The Albuquerque VFR sectional claims that the airspace table in the margin use local time, but some of the airspaces in the table cross timezone boundaries. Which  timezone do those airspaces belong to?
BRONCO 3 MOA is an example that crosses the New Mexico-Texas border and therefore from Mountain to Central Time:

See this excerpt from the margin which states that local times are used and lists the effective times for the Bronco 3 MOA:

So, in the case of the Bronco 3, are the listed "local" times MST/MDT or CST/CDT?

Welcome to aviation.SE! This question might be helpful

I agree that that question and probably this one as well are related. I'm hoping that the answer explains how to convert that airspace into UTC time because there are two different ways to do it depending on where in the airspace you are.

Good question. I don’t think I have ever seen the edge case addressed, but ForeFlight says it is Mountain Time. My guess is that since this is on the Albuquerque sectional chart that’s why Mountain is used.

The times listed on the margin of the VFR Sectional chart are generally local time. In fact, the effective times that the FAA lists are also published in local time. However, in the case of a Special Use Airspace (SUA) that covers multiple time zones, the FAA specifies which time zone is used for local time.
The FAA publishes these details of SUA in the JO 7400.10A "Special Use Airspace".
You ask specifically about the Bronco 3 MOA. In the 7400.10A, the following details are currently published for the Bronco 3:

So, while Fort Worth Center is the controlling agency, the times of use are given in Mountain Time. This makes sense since the using agency is out of Cannon AFB in New Mexico.

Compare this to the nearby Lancer MOA (entirely in Central Time) for which the 7400.10A only lists the time as "local time":

This is exactly the type of answer I was looking for, thank you!


text:
Is there a recommended time to pause before transmitting, after changing to a new frequency?
Does any aviation authority have a recommendation of how long to listen after changing to a new frequency before making a transmission?

source

It depends upon the frequency. Normally you wait a few seconds on a non-busy frequency. On a class B approach frequency if you don't hear anything for a few seconds then you need to check your radio etc.

I was always taught:

Change frequency
Give it a good 3 count
If no one is talking, transmit

The FAA just advises a pause as per the AIM [4-2-1] but gives no time specifically

a. Listen before you transmit. Many times you can get the information
  you want through ATIS or by monitoring the frequency. Except for a few
  situations where some frequency overlap occurs, if you hear someone
  else talking, the keying of your transmitter will be futile and you
  will probably jam their receivers causing them to repeat their call.
  If you have just changed frequencies, pause, listen, and make sure the
  frequency is clear.

You will also learn to anticipate the flow. For example if you hear a controller issue something you should expect to hear the aircraft read it back. Once you get a feel for the cadence of chatter you will have even less issues.

If you're on an arrival to Chicago or NYC during rush hour, you might spend 30 secs just waiting for any dead space at all to chime in.

My EASA compliant RT theory book states listen in for at least 5 seconds.
Whether that's a hard and fast regulation or a rule of thumb isn't stated, but the idea is you listen long enough to ensure nobody else is talking before opening your microphone.

Thx - I appreciate the intuitive logic and reference +1


text:
Which engine manual must a pilot legally use?
Many aircraft have engine/prop performance information provided by the manufacture such as Bonanza, Cessna, Mooney, etc AND the engine manufacture. The performance or recommended settings may vary between the two-- i.e. Bonanza E-series Continental engines with Hartzell props.
Additionally there may be pilot organizations or other reputable sources that diverge from these manuals. Such as operating the engine LOP (lean of peak).
As a pilot, does one manual have legal precedence or may I choose any source of data for operating the engine and prop?

Unless the operation you seek to perform violates a limitation (published specifically as a limitation in the "limitations" section of the POH, or a FAR), you're ok from a legal standpoint.

FAR Part 91, in a certificated plane, private piot in a private plane, you can fly however you'd like.  Charles Lindberg taught lean of peak to pilots on WWII to save fuel for long distance ocean flights.
Check the engine manual, you will find you can fly as lean of peak as you can manage.  I find it hard to do with carburated O-360 engine. Usually I lean out until it gets rough, then enrichen some.  I just had a 4-channel engine monitor installed, so now I can start experimenting and see how well it really does LOP, maybe playing with some carb heat to help stir up the air flow better.
With fuel injection engines, you can adjust/swap out the injectors to get better fuel flow into each cylinder for better lean adjusting.
Leaning helps maintain good fuel/air mixture so you don't run too rich and waste fuel.  If you check later year Manuals, you may find better direction on leaning for your engine as well.  For the Cessna Cardinal, I have a 1977 POH that I use to supplement my plane's 1973 POH, Cessna got smarter as time went on it seems and some things are covered better.
Flying commercially may be a different manner. There the Company may specify one thing over another, you may not have a choice.

You can buy a manual for the Engine from the Engine manufacturer, but it will not take into account the Propeller or the Airframe.
The manual from the Aircraft manufacturer includes parts of the Engine manual, but also takes into account the Propeller and the various interactions between the Engine, the Prop and the Airframe. (eg. RPM bands to avoid with this particular combination of Engine/Prop/Airframe). So the Aircraft manual is the one to follow.


text:
Do any countries besides the USA accept Basic Med?
Are other countries accepting Basic Med for flights through their airspace, for example the European Union?

(I've made this a community wiki answer so that others can add new information if/when things change.)
These countries allow US pilots to fly with BasicMed:

The Bahamas
Mexico (from 10 Dec 2019)

I marked this as the answer but would you please share where or how you found this?

@jwzumwalt It was in an AOPA email I got some time ago, and there's a bit of discussion on it in their forums too. AOPA's trying to persuade Canada and Mexico too, but it isn't easy. BasicMed isn't ICAO-compliant so each country has to decide individually to accept it or not, and most of them don't see it as a priority. They also don't want to allow foreigners to fly in their airspace with a 'lesser' medical than their own citizens require. And in the case of Canada, the US doesn't accept their class 4 medical here, so why should they accept BasicMed there? Politics, in other words :-)

According to AOPA:

The following countries authorize BasicMed privileges:

United States
Mexico
The Bahamas
The Dominican Republic
Puerto Rico
U.S. Virgin Islands
American Samoa
Northern Mariana Islands
Micronesia
Guam
Marshall Islands
Palau.

[Edited to abbreviate country names and put it in list format.]

Puerto Rico, US Virgin Islands, American Samoa, Northern Mariana Islands, and Guam are all part of the US.

Indeed they are.  I guess AOPA mentioned them in case there was any doubt as to the legality in U.S. territories.


text:
Can a lost aircraft get a DF Steer?
When I got my pilots license in 1975, a lost airplane could call almost any FSS and get a DF (Directional Finder) steer. The range was probably upto 30mi. I would request a practice one every 3-4 years. The last practice DF steer I did was 15-20yrs ago.
Can you still get DF Steers (or an equivalent) from FSS?

Direction finders outside of Alaska were decommissioned in 2007 as GPS and and ADS-B, as well as older technologies, have made the DF services obsolete. The DF services in Alaska were decommissioned in 2013.

Last time I asked an FSS about this (mid 2000's) they said if you called up lost they'd just ask you to squawk ident, ask the ARTCC who's scope you were on and then hand you off to them for radar service.

A lot of aircraft don't have transponders. DF used the com radio.


text:
What factors are involved in determining the spanwise pitching moment distribution?
Assuming that I have a known $C_M$ (pitching moment coefficient), $C_L^{'}$ (lift per unit span) and wing geometry, how would I determine the spanwise pitching moment distribution?
Which point on the section of the aerofoil would I take moments about?
Would the weight of a propulsive produce a pitching moment and hence affect the pitching moment distribution?

In order to answer this question you need to know the detailed construction of the wing. In particular, the elastic center of each wing section is important. A simple way to find it would be to cut a cardboard into the cross section of the wing. Adjust local thickness according to skin panel thickness. Now find the center of gravity of this piece of cardboard, and you know where the elastic center is. Note that this only works for a closed torsion box; open sections tend to have their elastic center outside of their circumference.
The Free Dictionary has this definition for the elastic center:

A point within a wing section at which application of a concentrated
  load will cause the wing to deflect without rotation. This is the
  point in the wing section at which rotation will occur when the wing
  is subjected to a twist.

Now you need to calculate the distance between the elastic center and the quarter point, around which the pitch moment coefficient is defined. This, multiplied by the local lift coefficient, will give you the offset moment which you need to add to the pitch moment in order to calculate the total moment twisting the wing.

Which point on the section of the aerofoil would I take moments about?

That depends what moments you want to know. Aerodynamic moments are defined around the quarter point. If you want to calculate the aeroelastic twist of the wing, you need to use the elastic center.

Would the weight of an engine produce a pitching moment and hence
  affect the pitching moment distribution?

Masses produce moments which depend on load factor while aerodynamic forces depend on dynamic pressure. Yes, you need to add masses and their moments around the elastic center, and you need to do this separately for each speed at which you do the calculation.

The man, the myth, the legend! Even a newbie like myself has heard of you.


text:
Can I take friends flying with a private pilot glider license?
In the US, will glider clubs let you take up friends in a two-seater if you have a private license? Or do you need a commercial license?

Glider PPL will suffice, did it yesterday and three or four times in the past three months.
That's me in the back seat preparing to take a co-worker for her first glider ride in a Grob-103:

In general, YES.
However, different clubs have different rules, so you will want to check with a given club.


text:
How do I plan TOC/TOD in an IFR flight plan that includes SIDs and STARs?
For a checkride, I'm being asked to plan an IFR cross-country from Miami Executive (KTMB) to Tampa International (KTPA), using SIDs, STARs and approaches.
I'm going to use MIA5.MIA (Miami Five Departure) to depart KTMB, then get radar vectors to the WINCO transition, then fly via V97 to LBV (La-Belle VOR) and then use LBV.BRDGE8 STAR (LBV, ROGAN, BRDGE, JSTRM, PIE), and then get radar vectors to the Final Approach Course and perform the approach at KTPA.
My question is, when choosing the fixes for the flight log how should I include Top Of Climb (TOC) and Top of Descent (TOD)?
For the SID, which one of these options should I use:
1) Write KTMB, TOC, DHP, WINCO
2) Write KTMB, TOC1, DHP, TOC2, WINCO
Option #2 has two TOCs because the SID states that I should maintain 2,000 or assigned higher altitude, and then expect my filed altitude 10 minutes after departure.
And then on the STAR, where should I place the TOD: after the LBV VOR or after ROGAN? And what altitudes should I write after LBV if I don't get a descend via clearance?

I've never heard of a top of climb point at 2000' when you plan to climb higher than that.  TOC and TOD happen when you reach your cruising altitude and when you leave it.  Intermediate level offs are not generally considered as TOC or TOD points.  What cruise altitude are you planning on using?  Have you asked your instructor these questions?

I'm not sure if there's a standard, 'correct' way to do this, but for planning purposes I'd just assume that your climb and descent aren't affected by the SID and STAR. Calculate them as if it were a VFR flight, in other words, based on the route you have.
The issue here is that you don't know what ATC is going to do. The SID says "maintain 2000 or assigned higher altitude" so it's possible that they just clear you directly to your cruising altitude. Or they might keep you lower for a while for traffic, or have you climb in multiple steps, or whatever. Unless you know the local ATC practices very well you can't plan accurately for that and even if you do know what altitude they assign 99% of the time, your flight might still end up in the 1% that gets other instructions. Ultimately, you have to deal with whatever ATC gives you.
It would be worth asking your instructor about this too. First, he may have a better answer than I do! Second, he may know what the local ATC procedures are in that area. And finally, since you mentioned a checkride he might have some insider knowledge on what the examiner expects or likes to see. However you end up planning it, you should be able to explain to the examiner how ATC's instructions might affect your time/fuel calculations.


text:
Why is autolanding ILS a thing, but not autotakeoffing ITS?
In this answer to the question of why zero-visibility landings are legal and routine but not zero-visibility takeoffs, the poster makes the following point:

When an aircraft lands in near zero visibility, it is a fully automated process that is actually done without input from the pilot. The pilots are only needed to taxi off the runway and park the aircraft. It is called "Autoland" and many of today's aircraft have it.
As of today no manufacturer has designed an aircraft with "Auto Takeoff" but I suppose it is not impossible.

(Emphasis added.)
Which seems odd, given that autolanding with an ILS is a mature technique using mature technology, and autotakeoffing with an ITS (instrument takeoff system) wouldn’t need much more on top of that (just some additional antennae on the aircraft’s tail and a couple new routines for the autopilot) - it’d mostly be pretty much an ILS running in reverse, something like this:

What’s the dealbreaker for an autotakeoff-supporting instrument takeoff system?

A failure, like a tire blowing or engine fire requires pilot intervention immediately. It would be better if the pilot as at the controls when it happened rather than having to disengage the automatic systems and play "catch up" with flying the plane. I'm sure this will get there at some point, but right now it's just better to have your hands on the controls and mind in the game during this critical phase.

@RonBeyer: Couldn't an autopilot be programmed to react to a failure like an flaming engine or exploding tyre, and do so more quickly than a human pilot could ever hope to do (like how we already have autospeedbrakedeployment for rejected takeoffs)?

Autoland exists at least in part because a pilot can't safely hit (the right part of) the runway (at the right speed and attitude) without visual references, so a lot of precision electronic guidance equipment is needed, and then even more equipment to ensure the first equipment is working correctly.
In contrast, the sky is much bigger than the runway. It's comparatively easy for the pilot to hit the sky even without visual references (provided vis is good enough to taxi out). So none of that fancy stuff is necessary.

the sky is much bigger than the runway [citation needed]

@Sanchises: I can vouch. My window is currently full of sky, and if there is any runway out there I cannot see it. Also, Google Sky vs. Google Runway.

@dotancohen - Clever. Real clever. Highlight of the weekend.


text:
Do modern aircrafts like 747/787/A320/A380 have some Plug and Play subsystems/sensors?
Do modern passenger aircafts like 747/787/A320/A380 have some sub-system or sensors which are plug and play that might include some kind of sensors or radars which comes as optional and can be used plug-play as and when needed as per the requirement?

This is a very broad question. Be specific by mentioning which plane, and which systems..!

I have edited a bit but I am not aware of any sub-system which is plug-n-play but it might include some kind of sensors which may or may not come in general but the  aircraft have the facility to plug-n-play it as per the needs like Night vision or SATCOM for some specific satellite etc

It wouldn't make much sense.
By definition "plug and play" would means that the avionics automatically and silently adapts to whether whether the optional device is present or not.
This would mean that if the device is physically fitted, but not in contact with the main avionics -- say, a wire might have broken or shaken loose recently -- then the cockpit instrumentation would look exactly as if it had never been there. This is not desirable: when something the pilot thinks will be available for the flight isn't actually available you want to tell him explicitly so he can decide whether the problem needs to be planned around or reacted to.
Of course there are limits to how much the plane can itself verify that it is whole and in working order -- that's why there are preflight checklists. But to spend engineering effort specifically on allowing it to fail silently when communication with one of the sensors is lost, that would be counterproductive.

@jCisco: I am specifically talking about error conditions that are electrically indistinguishable from the user unplugging the device (in which case it is clear how plug-and-play ought to be have) -- e,g, the plug being shaken loose by vibrations.

I understand the events presented, and depending on what has is disconnected from the system, it maybe irrelevant. The data output would be stateless in as many cases as possible, to engineer otherwise would be problematic.  That aside, yes a poor PnP system that provides user comfort at installation and fails at the mission critical role would be entirely unsuitable behaviour for an aircraft.  And if IBM/MS based PNP was utilized, it would not be up to the job  In the end PnP was a step to increasing sales and competition in the PC accessory/expansion market by enhancing user experience.

I will answer this from a US FAA regulations stand point, but you really have 2 questions here

Do modern passenger aircrafts like 747/787/A320/A380 have some sub-system

The answer to this in certain ways of looking at it is yes. Modern glass cockpit style aircraft use ARINC Data Busses to transfer the data from the sensors to the main flight computers. Depending on how you define subsystem one could argue that this data bus is in a way a sub system. I am not positive on how to actually set one up and if the devices simply plug into it and self registers or need to be manually installed and programed some how but there are sub systems on large planes that share resources.

...plug and play that might include some kind of sensors or radars which comes as optional

There are lots of requirements around aircraft instruments and the way I understand them there really is not a lot of "optional" stuff. There are with out a doubt redundant things and backup systems. With this in mind there are some systems like auto pilot that if it was not working the plane is still more than capable of flying. But as for critical flight instruments even if they are plug and play you don't really have the choice of not having them.
On a bit of a side not Aspen Avionics has recently released an all software AOA indicator that runs in their glass cockpit system. This was traditionally done with a mechanical device like this one that Garmin makes. Im not sure I would call the aspen unit plug and play as there is no physical device to plug in but it is a software plug in situation for their units and worth the mention.

Plug and play is a standard developed by IBM and Microsoft around the time windows 95 was released.  The old Plug N Play standard is an attempt to make device discovery and configuration a zero touch process for end users.
The PNP standard has moved on since that time, however I could imagine some computer devices in the avionics bay utilizing USB, ISA busses to communicate and may very well comply with PnP standards of some type.
The only key component really missing is the User and the Windows operating system.  So while discovery and auto-config, conflict resolution Plug N play protocols maybe present in the electronics onboard an aircraft, but likely not in support of the windows operating system.
In comparison to the PC based hardware bus systems, ARINC version 573 is the base level of functionality required from onboard data busses. Compliant equipment can communicate while allowing the FDR to capture the data.
More modern standards in the 600+ families of standards/products are designed for more modular treatment of the aviation equipment. Very similar to telecommunications rack equipment has developed since moving to digital.  With modular systems based on a chassis providing comms services and power to add in cards of different capabilities and purposes. Also integrating with other separate devices that integrate via ethernet or other standard protocols to deliver the necessary services.
Telecoms and ARINC is a reasonable comparison both in form factor, technical requirements and practices.  ARINC for example utilizes Harvard biphase encoding of data, pioneered in telecoms to avoid signal state corruption.
So in short, plug n play doesn't exist at least in standards on aircraft as a consumer would expect PnP to be.  Device, Windows OS, hardware interface and zero touch attempt at config the device.

Actually, this is an oversimplification at best. For example, the Amiga had hardware autoconfiguration support, which (with fairly minor differences) is essentially what later came to be known as "plug and play" about half a decade later.

"Plug and Play" started with MS & IBM as a trademarked term, but it has become a generic term much the same way "Kleenex" is the trade name for facial tissue, but has become a common name (in the US, at least) for that thing you blow your nose in, then discard.

Ex-avionics engineer here, albeit not for about 20 years.  I've never seen a piece of avionics hardware with anything resembling USB.  They are either directly connected to some other piece of kit or use buses which are proprietary to the aircraft industry and which do not require kit to be "registered".  Plugging in a different piece of kit with the same connector would simply not work.  There is just no requirement for it.


text:
How do aircraft stall warning systems work?
If an aircraft stalls, there are stall warning systems called as Stall computers. Anyone has idea how they predict that its a stall and how they raise the alarm/warning?

possible duplicate of What is the immediate cause of stall?

@rbp I don't think this is a dupe: this question is asking how stall warning systems work, the other question is asking what causes a stall

Agree with @Pondlife , this is more asking for a technological question trying to understand how previous question is reflected in a warning electronic system.

Audible Warning
On light aircraft there is a reed (much like used on a musical wind instrument) mounted on one wing root, which is angled such that at the Angle of Attack which would cause a stall, the reed "plays" which can be heard in the cockpit.
Here is a view of where this system is mounted on a Cessna:

(source: weekendcfii.com)
On some aircraft, it is a similar principle; however instead of a reed, it uses a fin which at critical AoA pushes a micro-switch which activates a buzzer/horn inside the cockpit.
Here is the assembly on a Beech 18:

(source: eaa1000.av.org)

So, if you ever see anyone doing this:

They are not kissing their aircraft for good luck, merely testing the stall warn as part of pre-flight checks!
Tactile Warning
In addition to an audible reed/buzz/horn, most aircraft also provide tactile feedback to the pilot of an impending stall. In purely mechanical aircraft the aerodynamic forces on the control surfaces are transmitted through the mechanisms and are felt directly by the pilot when approaching a stall. In hydraulic or fly-by-wire aircraft, this is provided by a mechanical "stick shaker" linked to the same system as sounding the audible alarm.

Since, as I understand it, stall is a combination of AoA and speed, I presume that the reeds and switches will not activate at the trigger AoA if the speed is high enough?

@FreeMan You can stall at any airspeed (see this question and this one) and in any attitude, only the AoA is important because that's what causes the airflow to separate from the wing

@Pondlife thanks for the clarification/reminder.

Recently, my kids were playing with "blowout" party favors. The sound reminded me of the reed-type stall warning in a Cessna.

This would be improved by adding information for typical jet aircraft (see other answer).

To say that the fin/switch is used on larger aircraft is a bit of a weird statement, it has nothing to do with aircraft size. You'll also find it on the Socata TB10 and 20 for example.

@falstro updated, you're right.

@Lnafziger do you really think I should update this answer in favour of leaving the other answer to its own merits? I've written about the sort of aircraft I have experience of, in honesty until I read the other answer I never knew that is how airliner-sized aircraft monitor stalls.

One of the goals of the site is to revise answers to make them better, so that ultimately we have that "one perfect answer" the the question.  It's the wiki part of the site, and the way that it is now, neither answer completely answers the question.  For what it's worth, I would not have added a second answer (since it is not a complete answer) but would have edited yours had I been @porcupine11.

He's not kissing it ...? Monsieur Mangetout, is that you? :-)

Large commercial aircraft typically rely on either Angle of Attack (AoA) Vanes or Differential Pitot Tubes (Smart Probes (PDF)) to supply input to flight computers for the purpose of calculating AoA.

AOA Vane
When the computer(s) calculate an AoA nearing the critical angle, an impending stall is communicated to the pilots. There are visual indications, such as those given on the speed tape and pitch limit indicators (PLI), and tactile indications such as the stick shaker and pusher. Here is a Boeing Article on AoA measurement (PDF). Figure 11 shows the indications on the primary flight display.


text:
Do runway markings vary from country to country?
I understand that most of the airports should follow FAA/ICAO for runway markings but most of the countries have their own standardization orgs. So, how much do the runway markings vary from USA to Europe?
Edit: We are mainly looking for the big commercial airplanes and not the smaller and private strips which handles only big jets for commercial operations.

Related

In my part of the U.S. there are numerous grass/gravel strips that have no markings as well as some paved runways that have no markings.

Thanks but We are mainly looking for the big commercial airplanes and not the smaller and private strips which handles only big jets for commercial operations. Question edited to be specific.


text:
Is there a difference between a chart and map?

Does the use or meaning of "chart" or "map" vary worldwide?
Is there a difference between a chart and map?

If you don't get a good answer here. you might also try english.SE

AERONAUTICAL CHART− A map used in air navigation containing all or part of the following: topographic features, hazards and obstructions, navigation aids, navigation routes, designated airspace, and airports. Commonly used aeronautical charts are:…
FAA Pilot Controller Glossary: https://www.faa.gov/air_traffic/publications/media/pcg_10-12-17.pdf

Colloquially, I would say not really, by definition yes.
I think the simplest way to put is is:

All charts are maps but not all maps are charts.

Websters defines a chart as

: map: such as
a : an outline map exhibiting something (such as
climatic or magnetic variations) in its geographical aspects
b : a map for the use of navigators

while they define a map as

a : a representation usually on a flat surface of the whole or a part
of an area
b : a representation of the celestial sphere or a part of it
c : a diagram or other visual representation that shows the
relative position of the parts of something

In other words, maps are outlines of part or all of something while charts contain potentially more information like that needed to navigate or identify airspace. Interestingly according to the definition, if used for navigation its a chart.

The way I understand it is... a map will usually show the ground and features that are attached to the ground (trees, masts, roads). Whereas a chart will also show none physical features such as airspace, graticules, etc.

When I asked this I really did not differentiate between the two. I gave this as an answer but there certainly is grey areas. For example a city street "map" often includes street names, highway exit numbers, recreational parks, political boundries, etc - none of which are visual geographical objects. But I enjoyed learning something.

I was taught that charts give information on three dimensions of space while maps only represent two dimensional information.
For example, In the VFR sectional chart above, the altitude of various air-spaces, airports and key landmarks are indicated.  For nautical charts, the depth of the water is indicated.

Despite a clear overlap in the definitions of the two words, I do see the common sense approach to this explanation - thanks.

Mathematically, (and technically), a Map is any one-to-one or one-to-many association between the items in one set (or list) and the items in another set or list. You can have a map between the items on the surface of the earth and the points on a chart, but you can also have a map between the cities in the country and the individuals who are the mayors of those cities, or between dates, and the events that took place on those dates, or between the colors in the spectrum, and the frequency of the light that generates the color, etc. etc.
Check out This Wikipedia article about "Mapping". In general, the result of any "Mapping" is a "Map" but only those maps that relate geographic or spatial (2D or 3D) points in space to a visual representation of those points are "charts".

The mathematical meaning of "map" is quite certainly not relevant here.


text:
Why is there such a large price difference between the A350 and B787?
What are the reasons for quite significant difference in price between the Airbus A350 and Boeing 787? List prices for the A350-900 and 787-9 are around 317 million USD and 190 million USD respectively.

Those prices are not the actual prices airlines pay for those planes. They get big discounts and more complex contractual terms. It's not like buying a box of pasta

@Afe you should put that as an answer.

@ Afe - you're paying way too much for pasta.  Who's your pasta guy?

I am aware of that however the typical discounts are pretty much the same for both: https://www.forbes.com/sites/afontevecchia/2013/05/21/boeing-bleeding-cash-as-787-dreamliners-cost-200m-but-sell-for-116m-but-productivity-is-improving/, https://simpleflying.com/airbus-reveals-on-average-airlines-get-50-off-airline-list-prices/

Those prices are not the actual prices airlines pay for those planes. They get big discounts and more complex contractual terms. It's not like buying a box of pasta.
In conclusion, you can't assume that the price difference means a different cost of the components for the manufacturer


text:
What are the reasons for the end of the dogfight era?
A lot of sources mention that a lot of modern era (5.Gen) fighter jet designs such as the F-35 are focussing on qualities and properties such as stealth, long-range attacks, and versatility just to name a few. It is often brought up that the era of dogfights is over. What was the reason for this shift of desirable qualities in air defense and combat?

Closely related

I thought about asking if the era is really over as a new question. Many experts thought that the era was over before the Vietnam war, but experience rapidly proved those experts wrong. So maybe history is repeating itself, and experts who predict that the era is over now are wrong; maybe in the near future autonomous drones will change everything. Anyway, it occurs to me that it would be better to edit your question to also ask if the era is really definitely over, rather than to ask a new question that may be flagged as a duplicate. If you agree please feel free to edit your question.

This has been debated many times on similar questions such as the one linked above.  I'm voting to close.

Or maybe the whole thing is just a duplicate.

Primarily this was driven by the invention of the guided missile which can be deployed far outside the range of bullets (making them a standoff weapon) and which can actively track the target autonomously ("shoot and forget").
With these two features, it no longer became necessary to maneuver close enough to another plane to shoot it down with bullets and to accurately track the target aircraft with one's own aircraft while doing so- which made WWI and WWII dogfighting skills unnecessary.

I beg to differ.  So does the US Military.

@MichaelHall, why not post your own answer? then I'll delete mine.

There are a bunch of great answers and discussions on the other linked question. This is a dupe, not worth rehashing in my opinion.


text:
On average, how many landings does a student pilot need before their first solo?
On average, how many landings does a student pilot need before their first solo?
I know it depends on individual students, but roughly what is the number?
Or you can just tell me your experience.

My log book says I was at 50 landings, with 23.1 ASEL hours for starting first solo. I got my PPL at 259 landings 80.6 ASEL hours and 26.6 PIC hours (log at time of issuance, so end of the test).

Please know that the number or landings or hours required to solo means almost nothing about you skill as a pilot.  I've see the 45hr wonder kids (who were very proud of that number, btw) ball up airplanes in very stupid ways and the 100hr PPLs go on to have really great expierences with GA.

Not sure what the average is. I had 93 landings logged and 22.7 ASEL hours on the day of my first solo, but I had a few hiccups that delayed my medical cert and my CFI moved away at about 17 hours so had to find a new one to sign me off. Finished PPL by 156 landings and 45.6 ASEL though!

IIRC it was 33 landings, technically slightly less is you count that the instructor did the first couple.  But that was in a glider (sailplane).  As a general rule, younger pilots will go solo faster - I remember reading that it was along the line of 20 + 2 per year of age over 18.  Also launch method makes a difference - aerotow students tend to go solo in fewer launches/landings that winch students because they tend to have more handling time per launch.
This might be interesting: http://www.scottishglidingcentre.co.uk/cost_to_solo.htm

For what it's worth given that in 1969 when I soloed attitudes were different I think, but at solo I had 8.5 hours of dual and 35 dual landings.I have this long-term, back-burner project to get my hours to my web page at https://terryliittschwager.com/logbook.php

I'm at 26 hours and 23 landings and still not soloed. I'm hoping I'm close, I think half of the time I have is on ground operations taking too long on a busy airport.

My logbook shows 29 landings, with 11 hrs logged in an Aircraft Single Engine Land aircraft (ASEL) when my instructor stepped out and sent me off on my first solo flight.
I think those figures were typical for students at my flight school. It is probably also fairly typical for students at most §141 flight schools, such as mine.
Now, there can be a significant difference between the experience of training under §61 and training at a §141 flight school. The schedule at §141 schools tends to be more fast-paced than what many students might experience doing §61 flight training. Since students must systematically complete the curriculum at §141 schools, a certain minimum level of experience will be in place before a student solos. However, this curriculum also lends itself to a student being ready to solo after a fairly defined period of time. A student training under §61 might take longer to be ready to solo due to a number of factors, including a possibly more relaxed training pace. On the other hand, §61 training can also give an instructor the freedom to solo a student after less time than might be typical.
I don't have any hard data outside of my own experience and what I have observed, but I would guess that a typical §141 student will solo after about 20-40 landings and 10-15 hours. I would guess that a typical §61 student will solo after about 20-60 landings and 10-25 hours.

Just for reference, I trained at a part 61 school and my numbers are similar, I soloed at 10 hours with about 25 landings. Granted I also got my license at 45 hours (where national average is closer to 70). But my training was spread out over a year (so it wasn't one of those 45 hours in 3 weeks things).

@RonBeyer Yeah, thats just it. I think §61 gives more room to allow even earlier solos in some cases. You hear about folks that soloed after 5 hours or so. I doubt that would ever happen under §141.

I generally sent my 61 students up between 10-15hrs.  Why would a 61 a school take longer than a 141?

Quick question, how do you type the § symbol?

@kevin: You type ALT, maintain it, and type 21 on the numerical keypad. Else you use charmap.

@Kevin What mins said. If you forget those keystrokes, Google 14 CFR 91 and copy the symbol from one of the pages just as you presumably did in your comment ;)

@acpilot I have little direct experience with §61 training. My observations and anecdotal evidence has led me to understand that some student's more relaxed training schedule leads to more experience before solo or certification.

I was about double these numbers, but I trained at a busy urban airport with lots of IFR and jet traffic, so you'd expect a CFI to be more cautious than at a non-towered airport where the student has the pattern to him/herself.

I was trained in the US Navy. My basic flight training was conducted at NAS Corpus Christi in the T-28 Trojan and consisted of 30 actual flights. This was average for a student Naval Aviator. Total actual flight time was 48.9 combined and 40.6 as first pilot. There were a total of 7.3 hours of instrument time, with 1.9 night time hours. Before my solo I had 148 landings.
The average flight time was 1.6 hours with 1.4 as first pilot. Average landings per flight were 5.

The T-28 Trojan was similar in looks to the A1 Skyraider. The Skyraider had a Wright R-3350-26WA radial engine with 2,700 HP. The Trojan had a Wright R-1820-86 Cyclone radial engine developing 1,425 HP. You could torque roll the Trojan!
It was an airplane that, in a sense, was wasted on a new student like me. It was a lot to handle for a new aviator, and at the time I was flying, it was old and often a pilot was faced with emergencies. I remember being airborne listening to an emergency of a solo pilot with smoke in the cockpit. It had a lot of power with its 9 cylinder radial engine.
At full throttle on engine checks at the end of the runway you had to press hard on the brakes, and could find yourself coming off the power as you skidded down the runway. When you released the brakes you had a lot of rudder in compensating for the prop wash hitting the vertical stabilizer. It was customary on your first takeoff not to put in nearly enough rudder. Whoa, that led to some interesting events.
When I finished my indoctrination at Pensacola I was given the choice to fly the new T-34 Turboprop or go to Corpus Christi and fly the T-28. When I saw the engine on that beast I knew exactly which aircraft I wanted to fly. Wish I had enough money to own one.


text:
Does any country issue daytime-only commercial licenses?
I got my PPL last year (EASA, UK) and I've always been interested in the commercial route. However, due to my red-green colour blindness I've failed the Ishihara, Farnsworth D15 and CAD vision tests which are accepted by the UK CAA to obtain an unrestricted medical. By now I've accepted that going all the way to ATPL might not happen for me, but I'm still interested in any other style of commercial flying that could remain an option.
My question is - can I theoretically get a CPL which would allow me to fly only during the day? Is there any such thing as a Class 1 medical which is restricted to daytime only, like my current Class 2? Can I get an IR with colour deficiency, or just not get one at all?
Of course getting a job is another matter, but I just want to know if I could theoretically fly for a living (or even just a side job) while accepting my colour deficiency as opposed to continually trying to fight it. I'm originally from the UK, but I'm interested in opportunities all around the world - in fact, I'm planning on spending the next few years in Australia, New Zealand and possibly Canada using the temporary visas they offer to UK citizens.

Are you asking about fixed-wing aircraft only? There are no night requirements for commercial glider or balloon in the US, for example.

I'm focussing on fixed-wing at the moment, but would be interested in other areas too!

In Australia you can get a class 1 medical whilst being colour-blind, limited to day VFR. Night flying over here is a separate rating and not incorporated into the PPL/CPL so it is optional - it might limit your job prospects but you can absolutely fly on a CPL here in daytime only.

Thanks for the info - that's interesting to know! Hopefully heading over there in a couple of months, so will try to ask around and see what people say! Either way, definitely going to do some flying when I'm there :)

@user3621637 you won’t regret it! 90% of the country has perfect weather year-round and some amazing scenery to fly over :)

Without your Class 1 you will not be able to get your CPL.
You could however finish CPL theory and get an Instructor Rating with your PPL and Class 2 Medical (plus the required 150 hours PIC and 200 hours total).
IR can be done with Class 2 Medical and an Class 1 Audiogram (hearing) test.

Thanks for the reply - yes, I actually looked at the details on the UK CAA website (and a few other countries' sites) for CPL requirements, and they all seem to stipulate a certain amount of night flying. For example, the UK CAA says 5 hours, comprising 3 hours of dual instruction and 1 hour of cross-country navigation and 5 solo take-offs and full stop landings at night. Perhaps I will spend the next few years building hours in different countries, then when I hit the 200 mark I'll look at getting my instructor rating.


text:
Why not leave an electric fuel pump on all the time?
This question is related to single-engined piston airplanes equipped with an electric fuel pump like the Piper Dakota/Arrow etc. The POH states that the fuel pump should be switched on for takeoffs/landing/approach and maneuvers.
I understand that the fuel pump is a backup system and switching it on provides an extra margin of safety in such situations. My question is, why does the POH recommend that we switch off the fuel pump after reaching a safe altitude (say 1000 ft). Wouldn't it be safer to just leave it on? Is there potential for harm in leaving the electric fuel pump on? Or this is done on common sense grounds: just to save maintenance and prolong the life of the backup system so that it is there when you really need it?

The electric fuel pump is used to provide an extra safeguard against fuel starvation during critical operations in siphon fed fuel systems where either there is an increased risk of this happening or where sufficient altitude does not exist to resolve a problem such has switching fuel tanks or during takeoff and landing operations.  While one could in theory continue to operate the electric fuel pump continuously throughout flight operations, it it not necessary and just adds additional wear and tear on the unit.

Found this in the Piper archer POH: The electric fuel pump should be normally 'OFF' so that any malfunction of the engine driven fuel pump is immediately apparent.

Yes but isn't much of aviation in general "not necessary and just adds additional wear and tear"?


text:
How can an aircraft’s maximum design operating speed be greater than its never-exceed speed?
According to this AAIB report on a June 2009 mid-air collision between an RAF Grob Tutor and a glider, the Tutor’s maximum design operating speed (VDO) is greater than its never-exceed speed (VNE):

(5) In the case of aerobatic category aeroplanes, allow each occupant to abandon the aeroplane at any speed between VSO and VDO10; [Quoting the applicable certification requirements for aircraft emergency exits; footnote in source.]

[...]
10 VDO is the maximum design operating speed which for the Tutor is 1.1 VNE or 205 kt. [The report’s explanation of the aforementioned footnote.  The bolding is mine.  Everything I have quoted from the report comes from page 62 (numbered as page 52).]

The point of the never-exceed speed is, as indicated by its name, that this speed should never be exceeded in this aircraft for any reason whatsoever; as such, aircraft are generally designed and certified with maximum operating speeds well below VNE.  How can the Tutor’s design maximum operating speed be greater than its never-exceed speed?

I don't understand the confusion here. Any other expectation is insane: The aircraft is designed to be able to fly up to a maximum of VDO and presumably may self destruct above that speed, so you don't want to even fly near that speed! It's pretty basic stuff: The only sane thing is to make VNE less than VDO, otherwise the expectation is that aircraft would routinely destroy themselves.

Maximum design operating speed means "we calculated the aircraft will break apart at that speed". It's obviously higher than the never-exceed speed, which means "you can safely operate the aircraft up to that speed".
Key here is the word "design". It always means something along the lines of "we calculated it to break at that load, please never try". The quotient of design load and maximum expected/allowed load is called safety factor. In this case, the safety factor is 1.1.

Hmm, do you have a source for that definition? I would have expected maximum design operating speed to be more like "long term operation at this speed will not exceed the fatigue limits of the airframe". Calculated to break apart at 1.1 times the Vne is cutting it quite close.

@jpa - If you fly 10-20% below flutter speed, everything is safe even in the long term. For "G"-loads, a safety factor of 1.5 must be demonstrated.

I'm no aviator, but shouldn't a definition of VDO be closer to "According to our schematics, calculations, and initial testing, the plane should technically be capable of withstanding this velocity, but we make no guarantees above it"?

There seems to be a mistake in the report. The glossary contradicts the footnote as to what Vdo is: Vdo Design Diving speed. The same thing which in the U.S. is called Vd: https://en.wikipedia.org/wiki/V_speeds#Regulatory_V-speeds

@Arthur As an Engineer, I'd agree with your definition.

VDO is the maximum speed, demonstrated in testing, that the structure is designed to handle (usually for flutter).
VNE is an operating limitation for the pilot to observe that includes a bit of safety margin below VDO


text:
Do glow plugs face fouling?
Do glow plugs face fouling? I understand that spark plugs foul on occasion, do glow plugs face the same issue?

Glow plugs are only used to aid starting of a compression-ignition engine. Once the engine is running, the glow plugs aren't used.

In most conditions, a diesel engine will start fine without glow plugs.  The glow plug controller on my car failed and I didn't replace it for over a year. The only problem was occasional difficult starting on really cold mornings.  I think you might be helped by reading some of the basics of how diesel engines work.

Additionally, a glow plug does not spark.  It is a simple electric heater coil and is therefore not susceptible to  fouling.

In many modern diesel engines, the ECU may keep the glow plugs on until temperature, time or RPM criteria are met. This is done to reduce emissions.

Fine wire glow plugs, vulnerable to fouling, are not used on manned aircraft.  Glow plugs in most diesel engines have massive elements where the coil is protected from being fouled.

It is worth noting that the fine wire glow plugs you mention really only have an application in model aircraft, not full-size aircraft. The theory and operation of those types of glow-plugs is substantially different than those used in diesel aircraft engines.

The glow plugs I have cut open have a single rather heavy gauge wire which is welded to the glow tube at the tip of the plug.  I believe that the tube is part of the heating element.  Typical current draws are 7 to 20 amp at 12 V and about half that at 24V for smaller, aircraft sized engines.


text:
What is the difference between Part 121, Part 135, and Part 91 operators?
What are the important differences between Part 121, Part 135, and Part 91 operators?

Your question is, at least in part, calling for opinions. The most important part operationally, in my personal opinion, is the requirement for 121 and 135 operators to have weather minimums before they can begin an approach. Part 91 operators can fly the approach without weather minimums, although if they arrive at minimums and do not have the runway environment in sight, they are supposed to do a missed approach. A caveat, I retired in 1999, so it's possible the regs have changed, although I don't believe they have in this respect. Perhaps someone else can comment on that.

Related, this answer to the question: What is the difference between Part 135 and Part 129?

So loose guidelines to match the loose question...
Pt 91 - generally private flying.  That is, no flying an airplane with paying customers unless those customers are government officials on government business.  This rare exception is called "public use"...it gets more complicated but let's leave it at this for now.
A rich guy who owns a jet to fly around in (or a company that owns a plane for business use) can be pt 91 as long as they don't sell seats or cargo space to the general public.
Pt 121 - scheduled commercial air service with paying customers.  Planes are flown on defined routes as often as the operator wants.  This is where companies like Delta and American operate.
Pt 135 - on-demand and scheduled charter.  When you call a company and say "take me (or my freight) fom LA to NY" you are likely talking about a pt 135 unscheduled charter. "Scheduled" charter is allowed but is limited to a few days a week (four, I think).


text:
Is an aborted landing considered an incident for the FAA?
I was a passenger on a commercial aircraft on final approach into Salt Lake City. As we desended to approximately 1000' the pilot suddenly gunned the engine, climbed and aborted the landing. He then explained that the landing was aborted as there was another aircraft on our runway.
Is this a reportable incident to the FAA?

It depends.
There are two general situations.  One where the other aircraft was supposed to be on the runway and one where it was not.
In order to increase traffic density and keep the system working, aircraft do not wait for the aircraft landing in front of them to clear the runway or, in single runway fields, for the aircraft taking off in front of them to get airborne.  The separation distances and times are such that normally, the other aircraft will clear the runway but sometimes it doesn't work out.  A departing aircraft might have been given a clearance to take-off but doesn't respond quickly enough, or a landing aircraft might have a problem causing the pilot to stop on the runway to check it out or perhaps simply missing the turn-off they were supposed to take.
ATC might see this happening before the landing aircraft does and issue an instruction to "go around" or, the pilot might have seen that the runway was not clear and made the decision to do so.
This happens around the world dozens of times a day and is not reportable.  The system worked as designed and safety was not compromised.  It is most likely to be what happened in your case.
The other situation is where the other aircraft should not have been on the runway, called a "runway incursion". It might have been instructed to "hold short" of the runway but then entered it or might have mistaken the runway for a taxiway.
This is reportable. The captain has the authority and the duty to ensure that the runway is, or will be clear when they land and to abort the landing if not.  If the captain cannot be sure, they are required to go around rather than press on in the hope that it will be clear. Again, the system worked but safety margins were compromised and thus, the incident is reportable, both by ATC and the landing captain.  If it was a runway incursion, the crew causing it, assuming that they realise that they made a mistake, are also required to report it.
Although I've mentioned aircraft, there are many things that might not be authorised to be on the runway such as people, ground vehicles, animals, construction equipment etc.  Occasionally, pilots are attempting to land on the wrong runway, perhaps one closed for maintenance, and will go around when they see stuff on it.  These are all reportable.

Fundamentally, a controller has two choices. He can always leave extra space or occasionally not leave enough space. The latter choice is more efficient, but it means that occasionally a landing will have to be aborted because another aircraft (either landing or departing) took longer than expected.

I'd also mention that landing abortions for weather issues (being it visibility, wind shear, ...) are in general also not reported. Maybe you shall tackle this to make the answer complete?

@yo The OP asks only about an occupied runway.  I don't see the point in cluttering the answer with every possible cause of a go-around.

@Simon Well, I don't read the question that way, but I agree it can be read either way. I read it as the title is, the reason for the go-around plays IMHO a little role there.

No, from your description this occurrence is probably not considered an incident, and probably would not require reporting to the FAA or NTSB.
A go-around, or aborted landing, is not inherently an incident, but is a relatively common procedure as the other answers have aptly explained. While the circumstances surrounding this go-around could possibly be classified as an incident (depending on what those unknown facts are), from your description this is unlikely.
The other answers are good, but I want to offer the FAA and NTSB definitions and regulations surrounding such an event.

Under FAA jurisdiction, the term incident is defined in 49 CFR 830.2:

Incident means an occurrence other than an accident, associated with the operation of an aircraft, which affects or could affect the safety of operations.

49 CFR 830.5 further defines various serious incidents which require providing immediate notification of the serious incident to the NTSB. The definition of a serious incident includes the following:

(12) Any event in which an operator, when operating an airplane as an
air carrier at a public-use airport on land:
(ii) Experiences a runway incursion that requires the operator or the
crew of another aircraft or vehicle to take immediate corrective
action to avoid a collision.

Given the above, your event would require notification to the NTSB if both the following were true:

It involved a runway incursion1, and
It required the crew of your aircraft to take immediate corrective
action to avoid a collision.

The first case is unlikely, but possible. This go-around could have been in response to an incursion, but most likely the aircraft on the runway was authorized to be there.2
The second case is less likely, especially given your description. In my estimation as a pilot for an air carrier, a go-around at 1000 feet above the runway does not constitute immediate corrective action. Those involved that day might have seen it differently. Note that at typical approach speeds it would take at least 1-1.5 minutes on the approach from 1000 feet above the runway to the point that the aircraft crossed the runway threshold. If we were to assume this event involved a runway incursion, the FAA would likely categorize this as a Cat C event3 (or possibly Cat B), which would be a relatively low severity event.
Moreover, even if the event did qualify as an incident, much less a serious incident, a report is only to be filed by specific request of the NTSB (see §830.15 below). In other words, even if the event was a serious incident requiring immediate notification to the NTSB, a report would only be filed at the NTSB's request.
See 49 CFR 830.15:

A report on an incident for which immediate notification is required by §830.5(a) shall be filed only as requested by an authorized representative of the Board.

1 The FAA defines a runway incursion as:

Any occurrence at an aerodrome involving the incorrect presence of an
aircraft, vehicle or person on the protected area of a surface
designated for the landing and take off of aircraft.

2 According to the FAA:

Approximately three runway incursions occur each day at towered airports within the United States.

From Runway Incursion Avoidance p. 2
Three incursions per day is significant, but given the daily number of aircraft and vehicle operations at towered airports within the United States, incursions are comparatively rare.

3 The FAA categorizes incursion incidents into four categories, ranging in severity from low to high, with Cat D being low, and Cat A being high severity. The highest severity level would be an accident. Only Cat A is considered to be a "serious incident" requiring notification to the NTSB. For more information see the FAA's Runway Safety page including the following definitions of Cat C and B incursion events:

Category C is an incident characterized by ample time and/or distance to avoid a collision.
Category B is an incident in which separation decreases and there is a significant potential for collision, which may result in a time critical corrective/evasive response to avoid a collision.

There are various safety events that must be reported by controllers. Some of these may be reported only via the Air Traffic Safety Action Program (ATSAP) (the controller's version of ASAP and ASRS), while some must be reported as a Mandatory Occurrence Report on the facility's daily log. Some examples are: Loss of airborne separation, loss of runway separation (runway incursion), bird strike, pilot deviation, any emergency or crash, etc.
One mandatory reporting event is: Turbojet aircraft go-around within one-half mile of the runway threshold (not in conjunction with a practice approach). This applies regardless of why the aircraft went around.
So:

If your aircraft actually got over the threshold of the runway before going around (and there was another aircraft on the runway), that would be a loss of runway separation and definitely reportable via ATSAP. The event should also be recorded on the facility log.
If your aircraft went around before the threshold but within a half-mile from it, there was no loss of separation but the event should still be recorded on the facility log.
If your aircraft went around outside of a half-mile from the threshold, no report is necessary. There was an unsafe situation (perhaps caused by the controller, perhaps caused by the pilot on the ground) and the controller took action to correct the situation in time.


text:
What are the standard stability derivative formulas and typical GA values?
What are the standard stability derivative formulas and typical GA values?
I suppose values for the C172 would be the best benchmark.

try this web page. However, it only lists the C182 and C310 besides other non-GA airplanes.

I don’t have it in front of me, but this book has the pertinent derivatives to consider, along with C172-ish values.
Aerodynamics, Aeronautics, and Flight Mechanics, 2nd Edition
Barnes W. McCormick
ISBN: 978-0-471-57506-1 September 1994 672 Pages


text:
What kind of batteries are allowed to be transported?
I am based out of India and I have to send two mobile phones along with batteries to Japan.  I thought of sending it by DHL.  This link gives information about regulations regarding the batteries.
I want to know whether the following batteries if put inside the phones and discharged is acceptable for courier or not:

A relevant paragraph at the end of the linked article is:

Due to the fact that PI965 is forbidden on passenger aircraft we offer
  a limited service. PI965 Section II requires separate dangerous goods
  account approval, since April 2016. For additional information please
  contact your local DHL representative. Lithium ion batteries packed
  with equipment (PI966) or contained in equipment (PI967) are
  acceptable for transport.

Does that mean if I pack the batteries inside the phones it is acceptable ?

To the OP: this seems to be more a passenger-side question, and we generally treat those as off-topic, since they are better handled on Travel.SE, see: https://travel.stackexchange.com/q/42411/26630

Hazardous Materials Regulations and handling is very much a part of the aviation transportation industry. This question does not appear to be about the passenger transportation aspect of hazardous materials (spare batteries are generally allowed in carry-on luggage only) but about the cargo shipment of batteries. That being said, I'm not sure that general HMR should really be on topic for this exchange. I am voting to close as this question is only tangentially aviation related. Legal might be a better place to ask.

Why don't you ask to DHL?

@mins they gave me the above link


text:
What is acceptable visual cue at Decision Height when performing CAT II approach?
For CAT II approach, the decision height is below 200ft but not lower than 100ft with RVR of 300m. In this case, if the aircraft is at 100ft above the ground, should the captain of that aircraft be able to see the runway threshold lights (green) at that moment? Or seeing the approach lights is considered sufficient to continue?

You can always edit your question...